Running GT-R in RWD

[druzilla32]

while the car is rolling, turn the car completly off (turn off turbo timer).. then turn the car back on while its still rolling..

this will keep ABS but will turn 4wd off

[druzilla32]

wait a couple of seconds before you turn the car back on otherwise it may cause the car to run in safe mode.

this will cause it to run STOCK BOOST EVEN IF THE BOOST RESTRICTOR IS REMOVED. amazing hey

[Beer Baron]

actually druzilla, on any 32 GTR i've tried the rolling shut-off, start up method on it disable both ABS and 4WD. This is because what happens when you switch on the car is the ABS/4wd computer does a sensor check, but you are still rolling so the computers think there is a faulty wheel speed sensor and shuts off the ABS and 4WD.

Pulling the engine bay 4WD fuse will disable 4WD only. ABS will still function.

I have extensively tested both methods.

[druzilla32]

my bad.. it was one of the 2

also it might not be the turning off/on quick that puts it in safe mode.. it could be turning it back on when the car is only JUST rolling. i remember turning it off to get RWD and turned it back on quickly cuz it was about to stop rolling.. then max boost was 8psi

also, what is better for the car/ABS while doing a burnout with the breaks on. having ABS on or off?? or does it not matter?

[Beer Baron]

it doesn't matter. BTW useing the 'rolling on/off' method when you want to go back to 4wd all you have to do is come to a complete stop. the ecu will complete it's sensor check/calibration and car will back back to ABS and 4WD on.

[qikstagea]

how about a stagea? i have a c34 (97) with r33 running gear, the atessa 4wd etc. ive tried removing the fuse, and yep it comes up 4wd. anyone else noticed that it locks the rear diff? it chirps something crazy when doing tight turns. drifts beautifully but. i figure having front drive shatfs would create a bit of friction - resistance, hey? anything to be done after you rip out the 4wd fuse in a stag?

[ish]

umm how do you convince a dyno operator that it is back at 2 wheel drive so he will put it on his dyno to tune it .. i have a r32 and i said i would turn off the front wheels and he still wont do it ...any suggestions ?

[Beer Baron]

very simple. pull out the 4wd fuse. get him to come out the front of the workshop, dial up about 4000rpm, let out the clutch, the resulting display should have him convinced the front are not transferring any torque to the ground... or more simply find another dyno equipped workshop that understands a 32 GTR can be switched to RWD only very easily.

[Darren W.]

How about we all stop pissing around with "roller dyno's" and start using "chassis" or "hub" dyno's. Just back it up, pack it up and jack it up- front wheels in the air so even if they do spin no drive!!!!

Thats how we do the 4WD drive cars on a 2WD set up.

Plenty of benifits with chassis dyno's such as "Dynapak" over cheaper more common roller dyno's.

Obviously you put the front end on stands after you jack it up.

Further more for added safety you can remove the front wheels to eliminate vibrations from the tyres and wheels.

[Duncan]

And how is dubbya bush, yankie?

Out of interest.....how good is it for the front cvs to be running at 180km/h at full droop?

remind me not to drop by your workshop

[Darren W.]

Was that in defence of roller dyno's??

Re-read my post I said "pack it up".

If you wanted a detailed procedure posted you could you could have asked and I would have. Then you would see that you dont need to subject the car to any stress such as you mention.

Sorry to all who cant figure out you need "axle stands" under lower control arms and body if needed- there you go! (If you cant work this out as a competent dyno operator and presumably mechanic then best you seek another career!!)

If he only has one set of axle stands dont go to his workshop either!!!!!!!!!!!!!!!!

May not always work as I havent tried every type of 4WD vehicle on the market either. But a method to try if all else fails for any stuck with a 4WD car at a 2WD dyno- just dont be a fool and gas it up to 180Km/h on the first run........ little steps first hey!!!

[R31 Gagz]

Hey,

Had my 32 gtr on a rwd dyno...just pulled the engine bay fuse and drove around the block to get rid of the pressure in the system. If its as simple as pulling the front shaft off though, will probably do that next time, dont have to worry then about the speculation on possibly damaging the clutches in the front transfer case and so on.

Cheers!

Gagz

[Darren W.]

We did that to a R32 GTR and found at high engine/g.box & transfer case RPM's (ie 4th gear) there was still some drag on the clutches and couldnt stop the front wheels turning. (rear on Dynapak front in the air) Maybe this is where the clutch damage story stems from, as with the front end of the car on the ground it maybe just slipping the clutches hardcore???

Yet the car drove like a 2WD on the road with the fuse pulled???

Has anyone else heard of this??

[R31 Gagz]

  Darren W. said:

We did that to a R32 GTR and found at high engine/g.box & transfer case RPM's (ie 4th gear) there was still some drag on the clutches and couldnt stop the front wheels turning. (rear on Dynapak front in the air) Maybe this is where the clutch damage story stems from, as with the front end of the car on the ground it maybe just slipping the clutches hardcore???

Yet the car drove like a 2WD on the road with the fuse pulled???

Has anyone else heard of this??

Yeah the car definitely drove like a rwd once the fuse was pulled....not a single bit of torque showed on the guage the whole time and there was plenty of reason for it to be there if it was connected

With the front in the air, it wasnt just the vibration making them spin or something? Where they turning at a good rate or just slowly moving and could stop it with your hand?

Cheers!

Gagz

Edited September 11, 2007 by R31 Gagz

[loaded34]

oops, I wrote something that had already been mentioned in this thread

Edited September 12, 2007 by loaded34

[Darren W.]

Turning fast and not like you could stop by hand???

Not like drive to the rears but definately from the transfer case (with the fuse out of course!!)

If in doubt jack it up and check for yourself or pull the front shaft.

Of those who have said no drive at all - how well bled and replenished do you keep your "ATESSA" & does anyone know how worn their clutches are at the time??

Alot of variables go into the wear factor of a car over its life (driving style, power, grip, size of tyres, road conditions, age etc....) and lets face it we are talking almost 20 years for the early systems through to the present day.

[Inline 6]

can someone please point out what fuse to yank out? some of us have faded fuse boxes that are very close to completely unreadable. ive been told its the top green 1 by the guys that stuck it on a 2wd dyno for me.

i tried pulling out this fuse and it worked least for a lil while, mines only stock so usually when i do a burnout it just takes off pretty much straight away this time i did a burnout and it was spinning to the point i had to ease off so i thought yeah rwd. it felt like it was rwd for a while but then after bout 10min i tried launching again and it gripped like it normally does in 4wd mode and i noticed the front torque gauge was moving around the same as usaul

i know the 4wd light turned on when they put it on the dyno but since then someone tried stealing my car and smashed my dash so when i got it fixed they just put a gts backing on my dials. im thinking that maybe covering up the spot where 4wd light shine's cause i aint seen it since.

i also tried the turn off and on while driving and had the same 4wd style. just seeen if you come to a complete stop after doing this the 4wd kicks back in, so that might have been my problem.

o and by the way that was a piss poor attempt of an arrow pointing to the front end of the car go penmenship

o 1 more thing ill just mention, my car has had the abs removed and hicas. not exactly sure why the abs been taken off, maybe to save weight or something who knows

Edited November 7, 2007 by gzilla

[heller44]

hope this helps you out.

When you pull the fuse in the engine bay, what you are doing is removing the power feed to the attessa actuator itself, the motor.

The abs/attessa computer still has power and will still try to operate,but will fault on 4wd.

If you get torque on the gauge and effort from the front wheels...., the possibly someone has arsed with your wiring.

james.

[Inline 6]

cheers for the pic, makes things a lot clearer.

sorry 1 last dumb question, are you guys taking out the fuse that says "4wd" in the passenger compartment or the 1 that says PTC Heater/4wd under the bonnet?

looks like i pulled out the anti skid fuse, didnt know the GTR even had anti skid. all this time thought i just had good throttle control

Edited November 7, 2007 by gzilla

[Beer Baron]

it doesn't have anti-skid.

there are two fuses you can remove. if you remove the engine bay 4wd fuse you loose 4wd but you still have ABS. if you remove the one in the cabin you loose 4wd and ABS. same thing if you switch off car whilst moving above 20kmh and restart whilst still moving you loose abs and 4wd. this is because the wheel speed sensors can't calibrate as the car is moving so they shut off abs and 4wd. as soon as you get below about 5kmh they will be able to recalibrate and you have 4wd and abs again.